The impact of circular economy and sustainability principles on construction quality planning and implementation

Ehitusinseneriõppe lõputöö Maaehituse õppekavalÜRO ja Euroopa Liidu liikmesriigina on Eesti võtnud kohustuse liikuda jätkusuutliku arengu suunas, mille eesmärk on parandada inimeste elukvaliteeti kooskõlas loodusvarade ja keskkonna talumisvõimega tagades seejuures täisväärtusliku ühiskonnaelu praegustele ja järeltulevatele põlvedele. Ehitatud keskkonna loomine mõjutab nii looduskeskkonda kui ka inimesi, kes selle keskel elavad ning jätksuutlikkuse ja ringmajanduse põhimõtete järgimine ehitatud keskkonna loomisel toovad kaasa muutused võrreldes sellega, kuidas varasemalt on ehitatud. Käesoleva lõputöö eesmärk on välja selgitada kuidas jätkusuutlikkuse ja ringmajanduse põhimõtted mõjutavad projekteerimise, ehitamise ja ehitise kvaliteeti. Analüüsi käigus sai kinnitust, et tegemist on väga aktuaalse teemaga, mille osas on nii Euroopa Liidu kui ka Eesti tasandil väga palju regulatsioone, kuid jätkusuutlikuks projekteerimiseks ja ehitamiseks ei ole Eesti tasandil valdkonnaga seotud strateegilistes dokumentides välja toodud konkreetseid põhimõtteid ja meetmeid, mida jätkusuutlikuks ehitamiseks oleks vajalik rakendada. Kavandatud eesmärgi täitmiseks viidi läbi ka personaalsed intervjuud erinevate ehituskeskkonna huvipooltega, kelleks olid tellijad, projekteerijad, ehitajad, valdkonnaga seotud riigiametite töötajad ja kasutajad. Kvalitatiivse sisuanalüüsi tulemustest selgus, et jätksuutlikkuse ja ringmajanduse põhimõtete rakendamise mõju projekteerimise ja ehitamise kvaliteedile on mitmesugune, sellele on ajaliselt sõltuvalt nii negatiivseid kui ka positiivseid aspekte. Jätksuutlikkust ja keskkonnahoidu peetakse oluliseks, kuid riikliku toe ja süsteemi puudumine, vähene teadlikkus ning majanduslikult ebatõhus keskkonnasäästlik mõtteviis ja käitumine ei ole täna Eesti ehitussektoris juurdunud. Antud töö selgitas välja ehitusturu hetkeseisu jätksuutliku ehitamise seisuskohast ning tõstis esile selle kitsaskohad.As a member of the United Nations and the European Union, Estonian government has responsibility to move towards sustainable development. The sustainable development goal is to improve people's quality of life in accordance with the carrying capacity of natural resources and the environment, thereby ensuring a full social life for current and future generations. The creation of the built environment affects both the natural environment and the people who live in it, and following the principles of sustainability and circular economy in the creation of the built environment will lead to changes compared to the way it was built in the past. The purpose of this thesis is to find out how the principles of sustainability and circular economy affect the quality of building design, buildings and construction. During the analysis, it was confirmed that this is a very topical issue, regarding which there are a lot of regulations both at the European Union and Estonian level, but for sustainable design and construction, there are no specific principles and measures that need to be implemented for sustainable construction in the strategic documents related to the field at the Estonian level. In order to fulfill the planned goal, personal interviews were also conducted with various stakeholders of the construction environment, which were clients, designers, builders, employees of state offices related to the field, and users. The results of the qualitative content analysis revealed that the impact of the implementation of the principles of sustainability and circular economy on the quality of design and construction is diverse, it has both negative and positive aspects depending on time. Sustainability and environmental protection are considered important, but the lack of state support and system, lack of awareness and economically inefficient environmentally friendly thinking and behaviour have not taken root in the todays Estonian construction sector. This work found out the current state of the construction market from the point of view of sustainable construction and highlighted its bottlenecks

Closed bore XMR (CBXMR) systems for aortic valve replacement: Investigation of rotating-anode x-ray tube heat loadability

In order to improve the safety and efficacy of percutaneous aortic valve replacement procedures, a closed bore hybrid x-ray∕MRI (CBXMR) system is proposed in which an x-ray C-arm will be positioned with its isocenter ≈1 m from the entrance of a clinical MRI scanner. This system will harness the complementary strengths of both modalities to improve clinical outcome. A key component of the CBXMR system will be a rotating anode x-ray tube to produce high-quality x-ray images. There are challenges in positioning an x-ray tube in the magnetic fringe field of the MRI magnet. Here, the effects of an external magnetic field on x-ray tube induction motors of radiography x-ray tubes and the corresponding reduction of x-ray tube heat loadability are investigated. Anode rotation frequency fanode was unaffected when the external magnetic field Bb was parallel to the axis of rotation of the anode but decreased when Bb was perpendicular to the axis of rotation. The experimental fanode values agreed with predicted values to within ±3% over a Bb range of 0–30 mT. The MRI fringe field at the proposed location of the x-ray tube mounted on the C-arm (≈4 mT) reduced fanode by only 1%, so x-ray tube heat loadability will not be compromised when using CBXMR systems for percutaneous aortic valve replacement procedures. Eddy current heating power in the rotor due to an MRI fringe field was found to be two orders of magnitude weaker than the heating power produced on the anode due to a fluoroscopic exposure, so eddy current heating had no effect on x-ray tube heat loadability